If any are in your stake, you may be able to see the phone numbers in the online directory for the ward in which their records currently reside. If you or someone else has a printed ward directory from before the records in question were moved out, you could pull any phone numbers from there. Other than that, I don't think the phone numbers of former ward members are generally available.
However, I thank you for leading me to find where to get the names and dates of birth of members moved out. That would be very useful in case of a need to retrieve a member whose records were moved out by mistake.